Treatment of benign prostatic hyperplasia is one of this nation's major health-care expenses, as evidenced by the fact that transurethral resection of the prostate is second only to cataract extraction as the major operation most costly to Medicare. For the approximately 450,000 prostatectomies performed annually in the United States, hospitalization expenses and physician charges (not including costs for nonoperative evaluation and treatment) approach five billion dollars. The surgical procedure constitutes over a third of the major operations performed by urologists, and the operative and the clinical activities associated with it involve nearly a quarter of the urologist's time. Mortality for the procedure has been reduced to 0.2% over the last 27 years, but the incidence of immediate postoperative morbidity:has remained unchanged at 18%. The high cost of the procedure, not only in physician time but also in medical expense and patient morbidity, has therefore caused urologists to seek cheaper and less morbid ways of treating patients with benign prostatic hyperplasia.
During the last decade, as a result, a variety of alternative treatment methods have been introduced, including watchful waiting, medical management using alpha blockers or androgen suppression, insertion of prostatic stents and coils, balloon dilation, prostatic hyperthermia, and transurethral incision. None of these methods has proved superior to transurethral resection, and the majority of patients with bladder-outlet obstruction continue to require hospitalization for this procedure to relieve their symptoms.
The procedure of transurethral resection includes the step of electrically heating an insulated loop of wire in a electrocautery device and slowly drawing the heated loop back and forth longitudinally within the prostate to cut and cauterize tissue, creating a series of furrows along the length of the prostate until the lumen has been treated circumferentially. This procedure typically takes 45-60 minutes of physician's time to perform and considerable skill. If areas are missed or inadequately treated, an unsatisfactory treatment may result. Glycine, sorbitol-mannitol solution or sterile water, which are not as physiologically biocompatible as saline, are used as a cooling fluid, because saline will short-circuit the electrical power used to heat the loop and can cause harm to the patient.
Transurethral resection typically results in three to six days of bed stay at considerable cost, one to two weeks of recuperation time, substantial post-operative pain and bleeding, and approximately 10% of the patients require a blood transfusion. Up to 5% of the men who undergo this procedure suffer incontinence, and impotence results in up to 15%.
Although transurethral laser prostatectomy has held great theoretical interest, it has heretofore been impractical because of the difficulties in simply, accurately and effectively directing light energy into the tissue of the prostrate. Urologists have attempted to apply laser photo irradiation for treatment of prostatic disease. McPhee, in Lasers in Urologic Surgery, 2d ed., Year Book Medical Publishers, Inc., Chicago, IL (1989), pp. 41-49 and in Lasers in Urologic Surgery, Year Book Medical Publishers, Inc., Chicago, IL (1985), pp. 94-102 describes employing light energy from a neodymium:YAG laser following transurethral prostatectomy in order to improve hemostasis and reports satisfactory postoperative voiding patterns. However, his technique was relatively cumbersome. Moreover, McPhee reports that he encountered some difficulty controlling bleeding of larger vessels at the vesical neck. Beisland and Sander, Urol. Res. 12:257-259 (1984) describe using light energy from a neodymium:YAG laser via a flexible laser cable three to four weeks after conventional transurethral prostatectomy in order to treat localized prostatic cancer, but report that it was found necessary to insert the flexible laser cable into the prostatic cavity through a suprapubic trocar cystoscope. While the procedure was well tolerated and void of serious complications, and while the preliminary results were encouraging, a surgical incision, albeit small, is still necessary, with the attendant risk of infection and extended hospital bed stay.
U.S. Pat. No. 4,445,892 to Hany M. Hussein, Marvin P. Loeb and Harvey S. Weiss teaches a dual balloon catheter device which is provided with two spaced and expandable balloons for occluding a segment of a blood vessel between the balloons. The dual balloon catheter device also includes a first channel for flushing the occluded segment, an optical system for use in the segment, a longitudinally movable and rotatable mirror or prism for directing light energy at an angle of 90.degree. to the axis of the catheter, and a second channel for introducing fluid into the blood vessel distally of the device. Such a device is likely to require the same 45-60 minutes of procedure time and a high level of operator skill.
U.S. Pat. No. 4,672,963 to Israel Barken teaches a surgical system for destroying unwanted internal structures which includes a laser device, an ultrasonic probe and a computer system. The ultrasonic probe provides data signals that are processed by the computer system to provide an image of the structures involved in the laser irradiation procedure. The laser device can be inserted in the body and, while moving through the obstructed lumen, is activated by the computer system to provide radiation capable of destroying internal tissue. By calibrating the effects of the laser device as a function of power, the surgical procedure can be controlled by including overlaying images of the regions already affected by the surgical procedures on the images previously provided by the ultrasonic probe. This image reconstruction can be performed in real time providing immediate feedback to the attending physician. The computer system can also monitor system parameters such as laser power. This system has particular application to procedures involving the prostate gland where the laser device can be inserted intraurethrally and the ultrasonic probe can be inserted intraurethrally or transrectally. However, this technique requires expensive equipment and, like conventional transurethral resection of the prostate, takes considerable time and skill.
U.S. Pat. No. 4,955,882 to Said I. Hakky teaches a resectoscope for prostate surgery which includes a rotating cutting element mounted within an outer sheath adapted to be inserted into the urethra. The cutting element has helical threads along the length thereof and a cutting blade at its distal end. The outer sheath has a covered distal end portion which extends beyond and over the cutting blade and has an opening therethrough adjacent the cutting blade. Within the outer sheath is an inner sheath surrounding the cutting element except for the cutting blade. An optical fiber which is optically coupled to a laser is positioned within the space between the inner and outer sheaths and extends along the length of the inner sheath to a position adjacent the cutting blade. The optical fiber is surrounded by a third sheath and is adapted to be moved by the rotation of the cutting element so that the beam of light energy from the optical fiber advances through tissue to cut and coagulate the resected area before the cutting blade of the cutting element reaches the resected tissue. Irrigation fluid is provided to the area between the inner and outer sheaths and is withdrawn through the inner sheath. A telescope is also provided through the cutting element of reviewing the area being resected. The lack of accuracy of such a cutting device, with the risk of damage to the bladder sphincter, perforation of the prostate and damage to the rectum and intestines, makes this device less desirable than conventional electrocautery resection.
U.S. Pat. No. 4,449,528 to David C. Auth, Dale M. Lawrence and Tim R. Majoch teaches a miniaturized, endoscopically deliverable thermal cautery probe for cauterizing internal vessels. The probe is applied to tissues cold. Thereafter, a relatively large number of electric heating pulses of equal energy is then applied to an internal heating element in the probe. The probe has an internal heating element in direct thermal contact with an active heat-transfer portion that has a low heat capacity to insure quick heating and subsequent cooling, thereby adequately coagulating tissue while minimizing heat penetration and resulting tissue damage. The electrical power applied to the probe is continuously measured and is terminated when the energy delivered reaches a preset value. The number of such pulses applied to the probe, hence the total energy delivered, may be present while the duration of the period during which the pulses were applied is displayed. Alternatively, the duration of the period during which such pulses applied, hence the total energy delivered, is displayed. The heating element for the probe is a controlled breakdown diode which as a breakdown voltage that is a function of its temperature so that the temperature can be controlled. Again, glycine is used as a cooling fluid, since saline cannot be used in the presence of an electrical device. The heating element has a resistance of greater than 0.5 ohm to provide adequate power dissipation with relatively low currents. A washing fluid, preferably flowing along the outside of the probe toward its tip, cleans blood from the tissue to be coagulated to make the source of blood more readily visible. The risk of excessive heat penetration from such a device to the rectum and intestine makes this device less desirable than conventional electrocautery resection.
U.S. Pat. No. 4,672,961 to David H. Davies teaches an apparatus and method for retrolasing plaque deposits in a coronary artery to remove the same, which includes a tip assembly on the end of a flexible inner tube containing optical fibers that are slidable along a guide wire. The top assembly includes a reflective surface rearwardly of a front face that directs light energy supplied through the optical fibers in a rearward direction through a window portion to a focal point externally of the tip assembly. The deposit is removed as the top assembly is moved in a rearward progression back through the deposit. Such a device entails the same to and from, longitudinal movement and periodic rotation as electrocautery resection to produce a circumferential result, requires a similar 45-60 minute procedure time and entails significant operator skill, without predictable results.
U.S. Pat. No. 4,646,737 to Hany M. Hussein and Marvin P. Loeb teaches a heat applying medical device for applying localized heat to a portion of a patient's body. Generally, the heat applying medical device includes a lights transmitting conduit and a heat generating element which converts transmitted light into heat. A suitable exterior tube can also be provided for guidance, strength and delivery of fluids. The heat applying medical device can be used to cauterize or destroy tissue, or alter or remove deposits from lumens. The heat applying medical device can also serve as part of a system which provides the light and measures the temperature of the element. While this device produces localized heating and ablation of tissue, the risk of heat penetration into adjoining tissues and organs makes it less desirable than conventional electrocautery resection.
Endometrial ablation of the uterus in females, using an electrocautery, like in resection of the prostate, involves slowly moving an electrically heated wire loop along the inner wall of the uterus under direct vision, cutting and coagulating tissue in furrows, until the entire inner surface of the uterus has been treated. The procedure generally takes 45-60 minutes of physician time and considerable skill. In addition to significant pain and bleeding, substantial fluid flow is required to distend the uterus, which can cause excess absorption of fluid by tissues and leakage into the abdominal cavity, with risk of infection. If an area is missed or inadequately treated, an unsatisfactory treatment may result, and inadvertent perforation of the uterus could be extremely dangerous to the patient.
U.S. Pat. No. 4,834,091 to Douglas E. Ott teaches a surgical technique which uses a neodymium:YAG laser to treat the uterus while the uterus is kept distended by the flow of saline into the uterine cavity. The surgical technique includes the hysteroscopic insertion of a retrievable ostial plug into the tubal ostia of each fallopian tube so that the saline does not flow through the fallopian tubes during the period of time in which the laser is used to treat the uterus. At the conclusion of the laser treatment, the retrievable ostial plugs are hysteroscopically retrieved and withdrawn. Such a system entails an even longer period of time and special skills in the placement of the ostial plugs, with little improvement in procedure safety.
U.S. Pat. No. 4,836,189 to Jimmie B. Allred, III, Richard A. Kokosa, Allan I. Krauter and Richard W. Newman teaches a video hysteroscope which has an elongated flexible insertion tube containing a video imaging head at its distal end, with a channel for a surgical laser fiber and a saline channel which emits a continuous stream of saline solution distally from the head. The articulation section is kept as short as possible, and is limited to a maximum deflection of about 30 degrees. This system again requires significant operator skill and 45-60 minute of procedure time, and the limited 30.degree. angle of deflection does not permit some portions of the uterus to be treated, resulting in an incomplete procedure and potential regrowth of the endometrium.